Isempty in while loop not working
조회 수: 3 (최근 30일)
이전 댓글 표시
Hello! this might be a rookies mistake but I really cant understand whats happening... I have the code below, there is a large vector and I need to find where's a value in it. if the value doesnt exist I want to keep lowering it until I find one that does.
So in this case 0.4 doesn't exist neither 0.3 nor 0.2 but 0.1 does. the problem is that matlab runs for ever with my while loop and doesnt return k=1....
alpha=[0.1 0.5 0.9 1.3 1.9];
theta=0.4;
k = find(alpha==theta);
angle=theta;
while isempty(k)
angle=angle-0.1;
k = find(alpha==angle);
fprintf('The solution did not converge for %.2f so the angle %.2f is used. Extend the number of iterations to obtain solution \n',theta,angle);
end
thanks in advance!
댓글 수: 0
채택된 답변
Stephen23
2017년 12월 15일
편집: Stephen23
2017년 12월 15일
"this might be a rookies mistake"
It is. The mistake occurs here:
alpha==angle
Small differences in the floating-point values mean that those values are actually different. Floating-point numbers have been explained a thousand times on this forum:
etc, etc, etc
Always use a tolerance when comparing floating point values.
추가 답변 (0개)
참고 항목
카테고리
Help Center 및 File Exchange에서 Loops and Conditional Statements에 대해 자세히 알아보기
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!